Ironic since their basic destroyer design was the best of all belligerents. If they had taken sonar/radar seriously from the beginning the war would have been much more difficult for us. The very last sets they were making were almost as good as ours but that was in 1945!
The IJN also never figured out how to employ their submarines as aggressively as the USN did from 8 December 1941 onwards. The Japanese blazed tactical and technological trails in many ways at the start of the Pacific War. But, they allowed the US to catch up and surpass them as they appeared to flounder.